Suspended monorail system

ABSTRACT

In a monorail system a lightweight vehicle is designed for suspension from an overhead rail by drive units extending upwardly from a longitudinal beam which defines the main support for the entire vehicle structure, and the drive units are characterized in particular by having drive wheels pivotally mounted to swing upwardly under running engagement with the rail from a line normal to the running surface of the rail, to increase the urging and pressure of the drive wheel against the running surface.

United States Patent [72] Inventor Frank P. Pettit Arvada,Colo. [21]Appl. No. 700,211 [22] Filed Jan. 24, 1968 [45] Patented Mar. 9,1971[73] Assignee Projects General of America Denver, C010.

[54] SUSPENDED MONORAIL SYSTEM 25 Claims, 10 Drawing Figs.

[52] U.S.Cl. 104/95, 105/30, 105/73, 105/153, 105/154, 105/156, 105/329,105/397, 296/31 [51] 1nt.Cl 1161b 3/02, B61c 13/04, B6ld 17/04 [50]Fieldol'Sear-eh l04/93,94; 105/146, 147, 148, 149, 150, 155; 296/31 (P);104/95; 105/30, 73, 154, 153, 156, 329, 397

[56] References Cited UNITED STATES PATENTS 2,608,163 8/1952 Martin105/153 3,056,359 10/1962 104/95 3,074,354 1/ 1963 104/93 3,101,6788/1963 104/95 3,129,671 4/1964 105/153 3,176,628 4/1965 105/73 928,4357/1909 Felts 105/156X 1,469,997 10/1923 Cornwall 105/156X 1,846,0212/1932 105/146 2,020,540 11/1935 Dunlap 1 [OS/[56X 2,162,688 6/1939Lawrence t 105/153 2,228,034 1/1941 Nelles 1 105/153X 2,623,475 12/1952Fraser t 104/95 3,023,045 2/1962 Cirami 296/31-P 3,100,458 8/1963 Bakeret a1 105/397 3,380,398 4/1968 Wainwright et a1 105/30 3,446,158 5/1969Pettit 104/95 FOREIGN PATENTS 211,619 7/1909 Germany 105/153 PrimaryExaminer-Arthur L. LaPoint Assistant Examiner-Howard BeltranAttorney-John E. Reilly ABSTRACT: In a monorail system a lightweightvehicle is designed for suspension from an overhead rail by drive units,

extending upwardly from a longitudinal beam which defines the mainsupport for the entire vehicle structure, and the drive units arecharacterized in particular by having drive wheels pivotally mounted toswing upwardly under running engage- Patented March 9, 1971 3,568,605

4 Sheets-Shani. l

' INVENTOR. E 3 FRANK F. PETTIT BY 1 Min l L) ATTORNEY Patented March 9,19 71 3,568,605

4 Sheets-Shani; 2

INVENTOR. FRANK P PETTIT ATTORNEY Patented March 9, 1971 4 Sheets-$heet5 INVENTOR. FRANK P PETTIT I ATTORNEY Patented March 9, 1971 4 Sheets-Sheet 4 ATTORNEY SUSPENDED MGNURAIL SYSTEM The present invention relatesto novel and improved monorail carrier systems and apparatus, and moreparticularly relates to a novel and improved vehicle and drive unitstherefor, the drive units being adaptable to suspend and to drive thevehicle along an overhead monorail.

Various types of monorail systems have been devised for transportingpassengers and cargo, but in the past their use and acceptance has beensomewhat limited, primarily due to their relatively high cost ofconstruction, maintenance and operation. customarily, the vehicle issuspended from an overhead rail by means of drive units selectivelyengageable with the rail, and particular difficulties have beenencountered in devising a drive unit capable of reversibly driving thevehicle in a positive, dependable manner while affording maximumstability and comfort at relatively high speeds.

it is therefore an object of the present invention to provide for anovel and improved monorail system of lightweight, sturdy constructionbeing adapted for high speed travel along an overhead rail and which iscapable of transporting relatively heavy loads of cargo or passengers athigh rates of speed safely and economically with maximum comfort andstability.

It is another object of the present invention to provide for a novel andimproved means of suspension of a lightweight monorail vehicle from anoverhead rail together with improved forms of drive units capable ofmaintaining a constant positive drive over extended track lengthsnotwithstanding variations in conditions on the track or changes inload.

It is a further object of the present invention to provide in a monorailsystem for a drive assembly capable of driving and advancing relativelyheavy loads at high rates of speed with comparatively low powerrequirements, is further capable of negotiating sharp turns withoutintroducing bending or twisting stresses with complete articulationbetween the vehicle and drive system as well as between the componentparts of the drive system, and in general assures greater flexibilitywhile maintaining firm frictional engagement between the driving membersand the running surfaces of the rail.

it is a still further object of the present invention to provide noveland improved forms of drive assemblies for monorail systems in which thedrive assemblies may employ either solid or inflatable rubber orrubberlike tire members which will effect maximum frictional engagementwith the running surface of the rail together with increased stabilityand flexibility in negotiating sharp turns or inclines while eliminatingthe need for flanged wheel assemblies.

in accordance with the present invention, a lightweight monorail vehiclemay be constructed almost entirely of fiberglass or other lightweightmaterials which are combined into a unitary structure and suspended froman overhead rail through a single .beam member traversing the uppercontrol section in the vehicle. Overhead drive units extend upwardlyfrom the longitudinal beam member for suspension from an overhead railwith the necessary source of motive power and control for the driveunits being housed in the upper control section so as to afford maximumspace in the vehicle for passengers or cargo.

Preferred and alternate forms of drive units are characterized by havingload wheels which sustain the weight of the vehicle by riding along theupper surfaces of the lower horizontal flange portions of the rail,guide wheels associated with the load wheels and engageable with thevertical section of the rail to minimize lateral displacement of thedrive units with respect to the rail, and one or more lower frictionaldrive wheels being pivotally mounted about an axis above the axis ofrotation and directly beneath the undersurface of the lower horizontalflange portion of the rail. The drive wheels are biased upwardly againstthe undersurface of the rail and when rotatively driven about their axesof rotation are free to be urged by running engagement with the railfrom a line normal to the undersurface angularly in an upward directionabout their pivotal axes to increase the pressure of the wheels againstthe undersurface of the rail and afford most positive advancement alongthe rail. The preferred form of invention is characterized by providingcomplete articulation between the load wheels, guide wheels and drivewheels where the wheels are composed of solid rubber or rubberliketires; or in the alternate form of invention inflatable tires may beutilized in place of solid tires to provide an extremely flexible,stable drive while avoiding the need for articulation between differentsections of the drive units.

The above and other objects, advantages and features of the presentinvention will become more readily appreciated and understood from aconsideration of preferred and alternate forms of the present inventionwhen taken together with the accompanying drawings, in which:

FIG. l is a top plan view with portions broken away to illustrate theinterior detail of the upper control section of a monorail vehicle.

FIG. 2 is a side elevational view of the monorail vehicle and track ofFIG. ll.

FIG. 3 is asectional view of the monorail vehicle and track of FIGS. 1and 2 showing the interior of the drive units and vehicle.

FIG. 4 is an end view of the monorail vehicle.

FIG. 5 is an end view partially in section illustrating the interior ofthe vehicle as shown in FIG. 4.

FIG. 6 is an enlarged view in detail of a preferred form of drive unit.

FIG. 7 is a top plan view in detail of the preferred form of drive unitshown in FIG. 6.

FIG. 8 is an end view partially in section of the preferred form ofdrive unit.

FIG. 9 is a fragmentary side view of an alternate form of drive unit;and

FIG. 10 is an end view of the alternate form of drive unit shown in FIG.9.

Referring to the drawings, there is shown in FIGS. l to 5 a monorailsystem broadly comprised of a passenger vehicle 10 suspended by upperdrive units 12 from an overhead track or rail R. Typically the rail maybe I-shaped or inverted T-shaped in cross section to provide a lowerhorizontal flange F and a vertical web section W extending upwardly fromthe midsection of the flange. In the preferred form, the vehicle is apassenger car constructed with an outer lightweight fiberglass shell 14of generally oval-shaped configuration having downwardly divergent sides15 and curved end sections 16 with plexiglass windows 17 interrupted byvertical moldings l8 and a side door or other closure portion 20.

The shell is suspended from an upper rigid framework 22 consisting of amain support member in the form of a solid longitudinal beam 23,generally rectangular in cross section, which traverses the entirelength of the upper section of the vehicle. A generally circular or ovalbeam 24 circumscribes the upper peripheral edge of the shell, andtransverse beams or tie bars 25 interconnect the longitudinal beam 23and outer beam 24 in order to transmit the load or weight of the vehiclefrom the outside into the central beam member. The upper section of thevehicle is covered by removable access panels 26 which, together with alower horizontal panel 2'7 secured to the underside of the beam 23 anddivergent sidewalls 28, forms a hollow interior space, and which spaceserves as a control section above therigid framework to house thenecessary equipment and accessories for operating the vehicle and driveunits in a manner to be described.

As illustrated in FIGS. 3 and 5, seats 30 are built into the lower wallof the shell and rest upon a horizontal floor section 32, and verticalhand rails 34 are mounted for extension between the floor section andupper section of the vehicle. Here the seats 32 have seat and backrestcushions 35 and 36 mounted in wooden frame 38 built into the wall of theshell directly beneath the window sections.

The vehicle is suspended from the rail R by a pair of upper drive units12 that are disposed in longitudinally spaced relation between oppositeends of the vehicle to uniformly distribute the load, and each driveunit is suitably enclosed within a streamlined fiberglass fairing 40.Broadly, each drive unit supports the vehicle through a hanger 41depending downwardly from a yoke 42 for mounting in the longitudinalbeam 23. The yoke in turn transmits the load of the vehicle into loadbrackets 43, each load bracket being operative to support pairs of loadwheels 44 on opposite sides of the monorail R to ride along the uppersurface of the lower horizontal flange portions. Guide wheels 45 arelocated fore and aft of each pair of load wheels to yieldingly engagethe vertical flange section of the rail, and a lower frictional drivewheel 46 is pivotally mounted about an axis above its axis of rotationand directly beneath the undersurface of the lower horizontal flange soas to urge itself upwardly to increase the pressure of engagementagainst the flange surface in driving the vehicle in either direction ofrotation.

Considering in more detail the construction and arrangement of each ofthe drive units 12 of the preferred form of invention, the hanger 41 hasa rod 48 terminating at its lower end in a circular base plate 49, andupwardly and inwardly inclined flanges 50 on diametrically oppositesides of the rod form conical bearing surfaces disposed within agenerally cupshaped, correspondingly inclined recess 51 in the undersideof the beam. The rod extends through a bore 52 communicating with therecess 51 on the beam and upwardly through an aligned bore 53 in theyoke 42. The upper terminal end of the hanger has a bearing member 54provided with a downwardly facing, hemispherical bearing surface adaptedfor disposition within a complementary recess 55 within the yoke 42, anda nut and washer assembly 56 serves to retain the bearing 54 on the endof the rod 48. The hanger may be assembled to suspend the vehicle formthe drive units by inserting the rod upwardly through the aligned bores52 and 53 in the beam and yoke members and by positioning the bearingmember 54 on the upper end of the rod and tightening the same by meansof the nut 56. In assembled relation the drive unit is therefore free toundergo a limited amount of rotation and tilting both with respect tothe yoke and to the vehicle.

In the preferred form, the yoke 42 is of generally semicircular orarcuate configuration and has oppositely directed arm portions 57 and 58curving upwardly from the lower, intermediate bearing portion for thehanger and terminating in horizontally directed end portions havinghollow bosses 59 for connection to each of the load brackets 43. Theyoke also carries a drive wheel support assembly which is defined by apair of pivot links 60 mounted in spaced parallel relation on oppositesides of the yoke, each link being formed by an inverted V-shaped armpivoted at one end 61 to opposite ends of a common pivot shaft 62. Theopposite ends 63 of the links 60 are interconnected by an element 64which rests upon a springloaded plunger 65 mounted on one side of theyoke opposite to that of the pivot shaft 62. In this relation the pivotlink arms form opposite sides of a common U-shaped member so that theclosed end 64 of the member rests against the spring-loaded plunger inthe yoke and the free ends are pivotally attached to the pivot shaft onthe opposite arm portions 58 of the yoke, the plunger serving primarilyas a wearcompensating device for the drive wheel 46. In turn, themidpoint or apex of each pivot link arm 60 is provided with a bore 66for lateral insertion of a common pivot pin 67, the latter supportingthe upper free ends of a generally U-shaped drive wheel support bracket68. Opposite sides of the bracket 68 may be suitably provided withaligned ball bearing races 70 for journaled support of opposite ends ofa drive shaft 71 of the drive wheel 46.

As best seen from FIG. 8, one end of the drive shaft 71 is rotativelyengaged by a variable displacement, hydraulic drive motor represented atP which is supported by an attaching plate 72 to one side of the drivebracket in outer spaced relation to the end of the shaft 71. As thedriving force is applied to the drive wheel in either direction ofrotation the effect will be to urge the drive wheel to swing from a lineor reference plane through the axis of the drive shaft 71 and of thepivot pin 67 perpendicular to the running surface of the rail angularlyin an upward direction and in the direction of advancement to increasethe pressure and resultant traction of the drive wheel against therunning surface.

Each of the load brackets 43 is similarly in the form of a U- shapedmember having interconnected lower closed end portions 74 extendinghorizontally in spaced relation beneath the undersurface of the rail andupwardly extending sides 75 in laterally spaced relation to oppositesides of the rail. A bolt member 76 has an upper enlarged bearingportion 78 provided with a downwardly facing, spherical bearing surfacewhich rests in a correspondingly shaped recess formed between theadjoining closed end portions of the bracket 43, the bolt 79 continuingdownwardly through the boss 59 with a suitable nut and washer assembly80 threaded on the lower end of the bolt 76. A pair of load wheels 44are arranged in longitudinally spaced relation to one another onopposite sides of the vertical section of the rail and each wheel has astub shaft 82 journaled for rotation in a bearing 83, there being a pairof bearings 83 adjacent to the upper surface in each side 75 of the loadbracket 43. In addition, guide wheels 45 are mounted in horizontalspaced relation forwardly and rearwardly of the sides 77 of the loadbrackets for rolling engagement with the vertical section of the rail.Each guide wheel is mounted by means of a horizontal guide arm 85 ofgenerally arcuate configuration which has its inner end secured by a pin84 directly beneath one of the bearings 83 on the side of the loadbracket, and its outer end is provided with a vertical bore to receive avertical shaft 86 for the guide wheel. The guide arm is mounted to biasthe guide wheel inwardly against the vertical section of the rail, and aspacer bolt 87 interconnects the intermediate portion of each guide arm85 and the side of the bracket.

As shown in FIGS. 6 to 8, the load wheels 44, the guide wheels 45 andthe drive wheels 46 are each formed of a solid or semipneumatic tirewhich may be suitably composed of a rubber or rubberlike material toprovide maximum frictional engagement with the running surfaces of therail; or, each of the tires may be composed of inner metallic hubscovered with a tread surface composed of a rubber or rubberlikematerial. In the relationship described, the load wheels are compressedagainst the horizontal flange portion of the rail by the load of thevehicle with the guide wheels urged into engagement with the verticalsection of the rail; and the drive wheels are caused to be urgedupwardly against the undersurface of the lower flange portionintermediately between the fore and aft load wheel assemblies of eachdrive unit. It will be noted that the load wheels, guide wheels anddrive wheels are provided with flat or rimless running surfaces andobviate the use of flanged wheels or guide rims to stabilize the driveunits on the rail. Furthermore, the drive units are completelyarticulated both with respect to one another and with respect to thevehicle and further the load wheels fore and aft of each drive wheel aresimilarly articulated with respect to the yoke and hanger so that eachdrive unit is free to follow a curved or inclined path of travelindependently of the other drive unit while remaining in firm engagementwith the rail or track.

A modified form of drive assembly is shown in FIGS. 9 and 10 andcomprises the same essential combination of elements as in the preferredform including a yoke 42' and a downwardly depending hanger 41. The yoketransmits the load of the vehicle through load brackets 43 at oppositeends of the yoke, the load brackets supporting pairs of fore and aftload wheels 44 on opposite sides of the vertical section of the rail;and guide wheels 45' are mounted on the load bracket intermediatelybetween each pair of load wheels. Further, in the modified form, a pairof drive wheels 46 are suspended by a support bracket 68' from each ofthe load brackets 43 at opposite ends of the yoke so as to provide apair of drive wheels working in cooperation with each of the load wheelassemblies, as opposed to the single drive wheel for each drive unit inthe preferred form of invention, in order to achieve greater driving andbraking power. The modified form of invention is particularly adapted topermit utilization of inflatable tires for the drive wheels, load wheelsand guide wheels so that if a tire should fail the necessary load anddriving force can be sustained by the other tires until the vehiclereaches a convenient stopping point for repair. At the same time, use ofinflatable tires permits high speed driving with greater deflection andavoids the need for articulated joints between the frame and tires, andwill also compensate more for uneveness in the rail or changes indirection.

in the modified form of drive unit the yoke 42 has an intermediateportion 59 in the form of a generally rectangular housing provided withan upwardly convergent hollow receptacle W for insertion of the upperend of the hanger rod 48', the latter being suspended from the yoke by anut and washer assembly 56'. A pair of arm portions 91 each formed of achannel beam member extend upwardly and outwardly in spaced relation toone another from opposite sides of the portion 89, and each pair of armsterminate in free end portions pivotally attached to opposite sides ofeach load bracket 43. in turn, each load bracket 43' is defined by arigid frame, generally U-shaped in cross section having oppositevertical sides 93 interconnected by horizontal closed end portions 94extending transversely of and in spaced relation beneath theundersurface of the rail. Each end of an arm portion 91 is attached tothe midsection of the bracket by extension of a suitable connecting pin95 through a transverse opening in the end portion 92.

The load wheels 44 are journaled for rotation about a shaft member 96extending inwardly from the upper front and rear corners on each side ofthe bracket. In turn a single guide wheel 45' is journaled on a shaft 9%extending upwardly from a supporting block ltlll mounted intermediatelyof the upper edge of each side 93, and the block is biased inwardly bypairs of spring-loaded pin members 102 inserted through the outer edgeof the block into engagement with the side of the bracket.

A pair of drive wheels 46 are supported in side-by-side relation beneatheach load wheel assembly on a common drive shaft 16M between oppositesides of the drive wheel support bracket 6%. The bracket 68 hasdownwardly directed triangular sides 11% interconnected by transverselyextending webs ltltl located at opposite edges of the sides forwardlyand rearwardly of the drive wheel. Further, the wheel-supporting bracket68 is suspended from opposite sides of the upper load bracket by apivotal bracket llll having opposite sides ill of inverted V-shapedconfiguration interconnected by transversely extending web portionsllll2. Each of the sides Ill has its apex pivotally secured to one side93 of the load bracket by a suitable pivot pin 114, a lower end of eachside lll being pivotally attached to an end of the bracket 68 and theopposite lower end being secured to the opposite end of the bracket 68by a spring-loaded bolt member 115 extending through spaced parallelconnecting flanges M6 and 117 on the bracket portions. A variabledisplacement hydraulic drive motor P is attached to one side ms of thebracket 68' to drivingly engage the shaft llll, the latter beingsupported in bearings B22 in the sides 1% of the bracket, and if desireda mechanical brake, not shown, may be attached to the bracket as forengagement with the opposite end of the drive shaft we so as to permitemergency braking for sudden stops.

The specific manner and means for mounting each of the drive assembliesfore and aft of the vehicle corresponds to that described and shown inthe preferred form of H68. 6 to 8 and r is therefore not illustrated forthe modified form. .A particular feature of the modified form ofinvention is that the U-shaped, oppositely directed bracket members forthe load wheels and drive wheels enables use of inflatable tires safelyat high speeds, since if one of the load or drive wheel tires shouldfail the load is automatically transferred by its bracket to the othertire or tires.

in each form of invention, the motor P or P for the drive assemblies maybe energized and controlled in operation by a conventional hydrauliccontrol system mounted in the upper control section, as partially shownin FIG. 1. Thus a source of hydraulic fluid under pressure isrepresented at S, and a drive pump 1) is suitably driven by an electricmotor M. in a conventional manner, electrical collectors C may bemounted on the top of the bus to generate electricity for the electricalmotor M as well as for lights 28 and other electrical accessories in thevehicle.

in the forms of invention set forth herein, the guide wheels willcooperate in resisting lateral displacement of the load wheels. Howeverwhere it is necessary to negotiate relatively sharp turns or curves atrelatively high speeds, additional stability is afforded through the useof guide wheels or rollers 130 projecting downwardly from the vehiclefor engagement with a lower guide rail 132. As shown, the guide wheels130 are journaled on supporting shafts projecting downwardly fromattachment to the floor section of the vehicle, and the wheels beingdisposed to engage the vertical sections of the rail to prevent swayingor tipping of the bus under high speeds of travel. Moreover, theemergency brake may be or may not be employed in either form of driveunit, since the variable displacement motor is self-locking when notenergized and the brake may be employed merely as an emergency brake forsudden stops.

The monorail apparatus of the present invention can support relativelyheavy passenger or freight loads while traveling at high rates of speed.For the purpose of illustration, the bus as described and shown in thepreferred form is designed to accommodate 50 passengers and has anunladen weight of 5,300 lbs. and, for instance, in utilizing a 15horsepower drive motor, the drive units are capable of attaining speedson the order of 10 to 12 miles per hour. In this connection, efficiencyis greatly increased in each form of invention by utilizing drive wheelswhich of their own urging will advance or swing upwardly into firmfrictional engagement with the undersurface of the monorail equally ineither direction of travel. For higher speeds of travel on the order of70 to miles per hour, a horsepower drive motor may be utilized inassociation with the inflatable tire drive unit of the modified forrn.Initial contact between the drive wheels and the rail is established bythe wear compensating, spring-loaded plunger elements as described, anadditional function of the plungers being to urge the drive wheelsagainst the rails in braking the bus.

From the foregoing, it will be evident that among other features themonorail apparatus of the present invention incorporates a positivereversible drive which is capable of maintaining a constant drivingpressure against the running surface of the rail in either directionover extended track lengths notwithstanding variations and conditions onthe track, changes in load or tire pressure while being capable oftransporting relatively heavy loads at highspeeds both safely andeconomically.

It is therefore to be understood that various modifications and changesmay be made in the specific construction and arrangement of elementscomprising the preferred and modified forms of drive assemblies eitherwhen used in association with the monorail system described or in othermonorail systems without departing from the spirit of the presentinvention.

1 claim:

1. Monorail apparatus adapted for suspension from an overhead monorailcomprising:

a vehicle having an upper framework extending the substantial length ofthe upper section of the vehicle; and

at least one drive wheel assembly mounted on said vehicle and engageablewith the overhead monorail, each drive wheel assembly including a drivewheel and drive motor therefor, suspension means to suspend said vehiclefrom the rail for advancement therealong with the drive wheel and drivemotor pivotally supported centrally within a space provided between thesuspension means and underside of the rail, and means associated withthe suspension means biasing said drive wheel into contact with therail, and a hanger extending upwardly from said framework for connectionat its upper end to said suspension means whereby said drive wheelassembly is freely and independently tiltable and rotatable with respectto said vehicle.

2. Monorail apparatus according to claim 1, each hanger defined by anelongated rod and including bearing members at upper and lower endshaving bearing surfaces in facing relation to one another, each of thebearing surfaces seated in complementary recesses in said suspensionmeans and said framework, respectively.

3. Monorail apparatus according to claim 1, said upper frameworkconsisting of a longitudinal beam extending centrally of the uppersection of said vehicle, transverse supporting ribs extendinghorizontally from opposite sides of said beam at longitudinally spacedintervals, and an outer peripheral beam in surrounding relation to saidribs.

4. Monorail apparatus according to claim 3, further including an upperdrive unit control section housed within said vehicle and supported onsaid upper framework.

5. Monorail apparatus according to claim 1, said vehicle having an outerlightweight shell formed of side and end panels of fiber glassconstruction diverging downwardly from connection with said uppersupporting framework, and a floor section at the bottom of said side andend panels.

6. Monorail apparatus according to claim 5, further including alongitudinally extending guide rail disposed in spaced relation beneaththe vehicle, and guide wheels depending downwardly from the floorsection of said vehicle for engagement with said guide rail as saidvehicle is advanced along the overhead monorail.

7. Monorail apparatus according to claim 1, wherein said drive unit isengageable with a rail having a lower horizontal flange portion, eachdrive unit including load-supporting wheels carried on said drive unitsupporting frame for engagement with the upper surface of said flange,and at least one drive wheel including a drive motor carried by saidsuspension means for engagement with the bottom surface of said flangeportion, said drive wheel pivotal about an axis vertically spaced abovethe drive wheel axis of rotation to undergo upward swinging movementabout its pivotal axis in response to rotation of said drive wheel forrolling advancement along the bottom surface of said flange.

3. Monorail apparatus according to claim 7, wherein said suspensionmeans includes;

a yoke having upwardly directed arm portions;

a load wheel supporting bracket at the upper end of each arm portion,said load wheel supporting bracket being of generally U-shapedconfiguration with opposite sides extending upwardly along oppositesides of the horizontal flange to carry pairs of inflatable tireload-supporting wheels in longitudinally spaced relation to one anotherfor rolling engagement with opposite sides of the upper surface of theflange, a drive wheel supporting bracket of generally U-shapedconfiguration having opposite sides extending downwardly from saidpivotal connection to opposite sides of each of said load-supportingbrackets; and

a pair of inflatable tire drive wheels pivotally suspended centrallybeneath said load-supporting wheels on each of said load-supportingbrackets.

9. Monorail apparatus according to claim 8, each of said drive wheelsupporting brackets including resilient means biasing said drive wheelupwardly against the bottom surface of the horizontal flange portion.

10. In an overhead monorail carrier system having a rail provided with ahorizontal flange portion, a drive unit comprising:

load-supporting wheels extending upwardly from said supporting frame forrolling engagement with the upper surface of the horizontal flangeportion;

a drive wheel supporting frame beneath the horizontal flange portion;

a rotatable drive wheel assembly including a drive wheel, saidsupporting frame including pivot means pivotally supporting said drivewheel to engage the bottom surface of the flange about a pivotal axisspaced above the drive wheel is at rest through the drive wheel axis ofrotation and normal to the bottom surface of the flanged portion wherebyto cause said drive wheel to undergo upward swinging movement about itspivotal axis in response to rotation of said drive wheel; and

drive means operable to rotate said drive wheel for rolling advancementalong the bottom surface of said flange portion.

11. A drive unit according to claim 10 wherein said drive wheel ispivotal in either direction away from the reference plane.

12. A drive unit according to claim 11, said load-supporting wheelsbeing flangeless, and said drive unit further including guide wheelscarried by said supporting frame for rotation about a vertical axis andincluding means to yieldingly urge said guide wheels into engagementwith a vertical surface portion on the monorail.

13. A drive unitaccording to claim 10, said pivot means pivotal about apivot link which pivotally connects to said supporting frame, said drivewheel pivotally connected to said pivot link in spaced relation to thepivotal connection of said pivot link to said supporting frame, andmeans biasing said link arm and drive wheel upwardly to urge said drivewheel against the bottom surface of said flange portion.

14. A drive unit according to claim 10, wherein two sets ofload-supporting wheels are disposed in fore and aft relation on saidsupporting frame, each set of load-supporting wheels including a pair ofwheels longitudinally spaced on opposite sides of a vertical section ofthe monorail, and said drive wheel being centered beneath said for andfore and aft load-supporting wheels between said supporting frame andhorizontal flange portion.

15. A drive unit according to claim 13 being further characterized byhaving a pair of drive wheels including a drive motor carried by saidsupporting frame, each of said drive wheels defined by an inflatabletire centrally located beneath each set of load-supporting wheels.

16. In a drive unit for a monorail carrier system and the like, saiddrive unit having a supporting frame with load-supporting wheels on saidframe for rolling engagement with an inner surface of a horizontalflange on the monorail together with lateral stabilizing meansassociated with said load-supporting wheels, the improvement comprising:

a rotatable traction drive wheel assembly pivotally supportedindependently of said load-supporting wheels for engagement with asurface of the horizontal flange on the side opposite to saidload-supporting wheels, said drive wheel assembly including pivot meanspivotally supporting said drive wheel about a pivotal axis spaced abovethe drive wheel axis of rotation and in a reference plane when saiddrive wheel is at rest through the drive wheel axis of rotation andnormal to the bottom surface of the flanged portion whereby to causesaid drive wheel to undergo upward swinging movement away from thereference plane against the surface of the flange as it is caused toadvance in either direction of travel along the rail.

17. In a drive unit according to claim 16, said drive wheel pivotalabout an axis relatively near the surface of engagement of said drivewheel with the flange and away from its axis of rotation.

18. In a drive unit according to claim 17, said pivot means defined by agenerally U-shaped drive wheel support bracket having opposed sides andspaced web portions interconnecting said sides, and said drive wheelbeing defined by a pair of inflatable tires mounted between the sides ofsaid bracket for rotation on a common axis of rotation.

19. In a drive unit according to claim 17, further including a pivotlink on said support frame and said drive wheel bracket pivotallyconnected to said pivot link to support said drive wheel for pivotalmovement with said pivot link while being pivotal independently of saidpivot link.

20. in a monorail system for suspension of a vehicle from an overheadmonorail, the monorail characterized by having a lower horizontal flangeportion and a vertical web section extending upwardly from and along themidsection of the flange portion, a pair of drive units spacedlongitudinally of the vehicle and extending upwardly therefrom forengagement with the monorail, each of said drive units comprising:

a suspension member suspended from the vehicle, a yoke secured to theupper end of said suspension member, said yoke being of generallyarcuate configuration to define oppositely directed arm portions curvingupwardly and outwardly from said suspension member to provide a spacebetween the yoke and themonorail;

load wheel-supporting brackets of generally U-shaped configuration eachswiveled to the upper ends of said arm portions and having oppositesides extending upwardly in spaced relation to opposite sides of thehorizontal flange portion of the monorail, loadrsupporting wheelscarried by opposite sides of each of said load-wheel-support bracketsfor rolling engagement with the upper surface of the lower horizontalflange portion of the monorail, guide wheels carried on opposite sidesof each of said brackets for rotation about axes perpendicular to theaxes of rotation of said load-supporting wheels,'and means yieldinglyurging said guide wheels against the vertical section of the monorailfor rolling engagement therealong;

a drive wheel in the space provided between the yoke and monorail and amotor drivingly connected to the drive wheel; and

a drive wheel-supporting bracket including means pivotally supportingsaid drive wheel about a pivotal axis spaced above the drive wheel axisof rotation and in a reference plane when said drive wheel is at restthrough the drive wheel axis of rotation and normal to the bottomsurface of the flanged portion whereby to cause said drive wheel toundergo upward swinging movement about its pivotal axis in response torotation of said drive wheel, and means on said drivewheel-supportingbracket biasing said drive wheel into tractionalengagement with the bottom surface of the horizontal flange.

21. In a monorail system according to claim 20, said drivewheel-supporting bracket further including a pivot link extendingbetween said arm portions of said yoke member, said pivot link pivotallyconnected at one end to one of said arm portions and means on the otherarm portion biasing the opposite end of said pivot link upwardly, saiddrive wheel-supporting bracket depending downwardly from pivotalconnection intennediately between opposite ends of said pivot link, saiddrive wheel carried for rotation by said support bracket about an axisof rotation spaced beneath the pivotal connection of said bracket tosaid pivot link and biased upwardly from said pivot link into tractionalengagement with the bottom surface of the horizontal flange.

22. In a monorail system according to claim 21, the point of pivotalconnection between said drive wheel support bracket and said pivot linkbeing below the bottom surface of the horizontal flange portion on themonorail.

23. In a monorail system according to claim 21, the pivotal connectionbetween said drive wheel support bracket and said pivot link being inspaced relation above the bottom surface of the horizontal flangeportion on the monorail.

24. In a monorail system according to claim 21 in which said guidewheels are positioned forwardly and rearwardly of opposite sides of saidbracket for rolling engagement with the vertical section of the monorailfore and aft of said load-supporting wheels.

25. ln a monorail system according to claim 20, wherein said loadsupporting wheels are each in the form of an inflatable tire, and therebeing a pair of drive wheelsupporting brackets each includinga pivotlink pivotally connected to one of said load wheel-supporting bracketswith said drive wheel-supporting bracket depending downwardly frompivotal connection at one end of said pivot link, and means at theopposite end of said pivot link biasing said drive wheel-supportingbracket upwardly, said drive wheel defined by a pair of inflatable tirescarried for rotation by each of said drive wheelsupportin brackets aboutan axis of rotation spaced beneath the prvota connection of said bracketto said pivot link and

1. Monorail apparatus adapted for suspension from an overhead monorailcomprising: a vehicle having an upper framework extending thesubstantial length of the upper section of the vehicle; and at least onedrive wheel assembly mounted on said vehicle and engageable with theoverhead monorail, each drive wheel assembly including a drive wheel anddrive motor therefor, suspension means to suspend said vehicle from therail for advancement therealong with the drive wheel and drive motorpivotally supported centrally within a space provided between thesuspension means and underside of the rail, and means associated withthe suspension means biasing said drive wheel into contact with therail, and a hanger extending upwardly from said framework for connectionat its upper end to said suspension means whereby said drive wheelassembly is freely and independently tiltable and rotatable with respectto said vehicle.
 2. Monorail apparatus according to claim 1, each hangerdefined by an elongated rod and including bearing members at upper andlower ends having bearing surfaces in facing relation to one another,each of the bearing surfaces seated in complementary recesses in saidsuspension means and said framework, respectively.
 3. Monorail apparatusaccording to claim 1, said upper framework consisting of a longitudinalbeam extending centrally of the upper section of said vehicle,transverse supporting ribs extending horizontally from opposite sides ofsaid beam at longitudinally spaced intervals, and an outer peripheralbeam in surrounding relation to said ribs.
 4. Monorail apparatusaccording to claim 3, further including an upper drive unit controlsection housed within said vehicle and supported on said upperframework.
 5. Monorail apparatus according to claim 1, said vehiclehaving an outer lightweight shell formed of side and end panels of fiberglass construction diverging downwardly from connection with said uppersupporting framework, and a floor section at the bottom of said side andend panels.
 6. Monorail apparatus according to claim 5, furtherincluding a longitudinally extending guide rail disposed in spacedrelation beneath the vehicle, and guide wheels depending downwardly fromthe floor section of said vehicle for engagement with said guide rail assaid vehicle is advanced along the overhead monorail.
 7. Monorailapparatus according to claim 1, wherein said drive unit is engageablewith a rail having a lower horizontal flange portion, each drive unitincluding load-supporting wheels carried on said drive unit supportingframe for engagement with the upper surface of said flange, and at leastone drive wheel including a drive motor carried by said suspension meansfor engagement with the bottom surface of said flange portion, saiddrive wheel pivotal about an axis vertically spaced above the drivewheel axis of rotation to undergo upward swinging movement about itspivotal axis in response to rotation of said drive wheel for rollingadvancement along the bottom surface of said flange.
 8. Monorailapparatus according to claim 7, wherein said suspension means includes;a yoke having upwardly directed arm portions; a load wheel supportingbracket at the upper end of each arm portion, said load wheel supportingbracket being of generally U-shaped configuration with opposite sidesextending upwardly along opposite sides of the horizontal flange tocarry pairs of inflatable tire load-supporting wheels in longitudinallyspaced relation to one another for rolling engagement with oppositesides of the upper surface of the flange, a drive wheel supportingbracket of generally U-shaped configuration having opposite sidesextending downwardly from said pivotal connection to opposite sides ofeach of said load-supporting brackets; and a pair of inflatable tiredrive wheels pivotally suspended centrally beneath said load-supportingwheels on each of said load-supporting brackets.
 9. Monorail apparatusaccording to claim 8, each of said drive wheel supporting bracketsincluding resilient means biasing said drive wheel upwardly against thebottom surface of the horizontal flange portion.
 10. In an overheadmonorail carrier system having a rail provided with a horizontal flangeportion, a drive unit comprising: load-supporting wheels extendingupwardly from said supporting frame for rolling engagement with theupper surface of the horizontal flange portion; a drive wheel supportingframe beneath the horizontal flange portion; a rotatable drive wheelassembly including a drive wheel, said supporting frame including pivotmeans pivotally supporting said drive wheel to engage the bottom surfaceof the flange about a pivotal axis spaced above the drive wheel is atrest through the drive wheel axis of rotation and normal to the bottomsurface of the flanged portion whereby to cause said drive wheel toundergo upward swinging movement about its pivotal axis in response torotation of said drive wheel; and drive means operable to rotate saiddrive wheel for rolling advancement along the bottom surface of saidflange portion.
 11. A drive unit according to claim 10 wherein saiddrive wheel is pivotal in either direction away from the referenceplane.
 12. A drive unit according to claim 11, said load-supportingwheels being flangeless, and said drive unit further including guidewheels carried by said supporting frame for rotation about a verticalaxis and including means to yieldingly urge said guide wheels intoengagement with a vertical surface portion on the monorail.
 13. A driveunit according to claim 10, said pivot means pivotal about a pivot linkwhich pivotally connects to sAid supporting frame, said drive wheelpivotally connected to said pivot link in spaced relation to the pivotalconnection of said pivot link to said supporting frame, and meansbiasing said link arm and drive wheel upwardly to urge said drive wheelagainst the bottom surface of said flange portion.
 14. A drive unitaccording to claim 10, wherein two sets of load-supporting wheels aredisposed in fore and aft relation on said supporting frame, each set ofload-supporting wheels including a pair of wheels longitudinally spacedon opposite sides of a vertical section of the monorail, and said drivewheel being centered beneath said for and fore and aft load-supportingwheels between said supporting frame and horizontal flange portion. 15.A drive unit according to claim 13 being further characterized by havinga pair of drive wheels including a drive motor carried by saidsupporting frame, each of said drive wheels defined by an inflatabletire centrally located beneath each set of load-supporting wheels. 16.In a drive unit for a monorail carrier system and the like, said driveunit having a supporting frame with load-supporting wheels on said framefor rolling engagement with an inner surface of a horizontal flange onthe monorail together with lateral stabilizing means associated withsaid load-supporting wheels, the improvement comprising: a rotatabletraction drive wheel assembly pivotally supported independently of saidload-supporting wheels for engagement with a surface of the horizontalflange on the side opposite to said load-supporting wheels, said drivewheel assembly including pivot means pivotally supporting said drivewheel about a pivotal axis spaced above the drive wheel axis of rotationand in a reference plane when said drive wheel is at rest through thedrive wheel axis of rotation and normal to the bottom surface of theflanged portion whereby to cause said drive wheel to undergo upwardswinging movement away from the reference plane against the surface ofthe flange as it is caused to advance in either direction of travelalong the rail.
 17. In a drive unit according to claim 16, said drivewheel pivotal about an axis relatively near the surface of engagement ofsaid drive wheel with the flange and away from its axis of rotation. 18.In a drive unit according to claim 17, said pivot means defined by agenerally U-shaped drive wheel support bracket having opposed sides andspaced web portions interconnecting said sides, and said drive wheelbeing defined by a pair of inflatable tires mounted between the sides ofsaid bracket for rotation on a common axis of rotation.
 19. In a driveunit according to claim 17, further including a pivot link on saidsupport frame and said drive wheel bracket pivotally connected to saidpivot link to support said drive wheel for pivotal movement with saidpivot link while being pivotal independently of said pivot link.
 20. Ina monorail system for suspension of a vehicle from an overhead monorail,the monorail characterized by having a lower horizontal flange portionand a vertical web section extending upwardly from and along themidsection of the flange portion, a pair of drive units spacedlongitudinally of the vehicle and extending upwardly therefrom forengagement with the monorail, each of said drive units comprising: asuspension member suspended from the vehicle, a yoke secured to theupper end of said suspension member, said yoke being of generallyarcuate configuration to define oppositely directed arm portions curvingupwardly and outwardly from said suspension member to provide a spacebetween the yoke and the monorail; load wheel-supporting brackets ofgenerally U-shaped configuration each swiveled to the upper ends of saidarm portions and having opposite sides extending upwardly in spacedrelation to opposite sides of the horizontal flange portion of themonorail, load-supporting wheels carried by opposite sides of each ofsaid load-wheel-support brackets for rolling engagement With the uppersurface of the lower horizontal flange portion of the monorail, guidewheels carried on opposite sides of each of said brackets for rotationabout axes perpendicular to the axes of rotation of said load-supportingwheels, and means yieldingly urging said guide wheels against thevertical section of the monorail for rolling engagement therealong; adrive wheel in the space provided between the yoke and monorail and amotor drivingly connected to the drive wheel; and a drivewheel-supporting bracket including means pivotally supporting said drivewheel about a pivotal axis spaced above the drive wheel axis of rotationand in a reference plane when said drive wheel is at rest through thedrive wheel axis of rotation and normal to the bottom surface of theflanged portion whereby to cause said drive wheel to undergo upwardswinging movement about its pivotal axis in response to rotation of saiddrive wheel, and means on said drive wheel-supporting bracket biasingsaid drive wheel into tractional engagement with the bottom surface ofthe horizontal flange.
 21. In a monorail system according to claim 20,said drive wheel-supporting bracket further including a pivot linkextending between said arm portions of said yoke member, said pivot linkpivotally connected at one end to one of said arm portions and means onthe other arm portion biasing the opposite end of said pivot linkupwardly, said drive wheel-supporting bracket depending downwardly frompivotal connection intermediately between opposite ends of said pivotlink, said drive wheel carried for rotation by said support bracketabout an axis of rotation spaced beneath the pivotal connection of saidbracket to said pivot link and biased upwardly from said pivot link intotractional engagement with the bottom surface of the horizontal flange.22. In a monorail system according to claim 21, the point of pivotalconnection between said drive wheel support bracket and said pivot linkbeing below the bottom surface of the horizontal flange portion on themonorail.
 23. In a monorail system according to claim 21, the pivotalconnection between said drive wheel support bracket and said pivot linkbeing in spaced relation above the bottom surface of the horizontalflange portion on the monorail.
 24. In a monorail system according toclaim 21 in which said guide wheels are positioned forwardly andrearwardly of opposite sides of said bracket for rolling engagement withthe vertical section of the monorail fore and aft of saidload-supporting wheels.
 25. In a monorail system according to claim 20,wherein said load supporting wheels are each in the form of aninflatable tire, and there being a pair of drive wheel-supportingbrackets each including a pivot link pivotally connected to one of saidload wheel-supporting brackets with said drive wheel-supporting bracketdepending downwardly from pivotal connection at one end of said pivotlink, and means at the opposite end of said pivot link biasing saiddrive wheel-supporting bracket upwardly, said drive wheel defined by apair of inflatable tires carried for rotation by each of said drivewheel-supporting brackets about an axis of rotation spaced beneath thepivotal connection of said bracket to said pivot link and biasedupwardly by said pivot link into tractional engagement with the bottomsurface of the horizontal flange.